Is there a function to display text in the R window? and how to display text written with HTML shaping?
See https://www.rdocumentation.org/packages/gplots/topics/textplot
As for HTML, I'm not sure how this makes sense - is this your R window of your web browser?
It is not clear what you mean by "R window", but it printwill print the text:
print
print("Hello World")
or
x <- "Hello World" print(x)
gives
[1] Hello World
Documentation